Active RFID (radio frequency identification) tags, such as WiFi RFID tags, are employed in many applications. For example RFID tags can be used for asset tracking or location determination. For example, in a hospital RFID tags can be used to enable medical personnel to locate equipment such as heart monitors or defibrillators.
Some RFID tags announce their presence periodically by sending a multicast packet, such as a layer 2 802.11 multicast packet, to a network without associating to an access point (AP). The AP is setup to allow packets to the known multicast address to be forwarded to a controller or other device on the network. Because these tags do not associate with the WLAN (wireless local area network) at all, all configuration or management of the tag is performed using an out-of-band mechanism, such as a CLI (command line interface) that uses a separate serial interface.
Some RFID tags associate to the WLAN, allowing them to be managed effectively over the air. However, these tags remain associated to the WLAN and do not revert to an unassociated mode of operation. This has a significant impact on the tags battery life as well as on the resources of the wireless controller and/or AP of the WLAN, and does not enjoy the advantages of an unassociated tag.